Objective:
Incremental cardiopulmonary exercise testing (CPET) is recommended to evaluate severity, prognosis and responses to therapy in patients with pulmonary hypertension.
We aimed to evaluate the impact of CPET in pulmonary arterial hypertension (PAH) patients risk stratification.
Design and method:
45 patients with PAH (mean age 43,1 + 11,0 years) underwent exercise on cycle ergometry. Oxygen uptake (VO2), carbon dioxide output (VCO2), expiratory gas concentrations and minute ventilation (VE) were measured breath-by-breath. Peak VO2 was defined as highest average of VO2 in the last minute of exercise.
Results:
The majority of patients (n = 16) had III functional class (World Health Organization (WHO) classification). The mean values of right atrial area and right ventricular size were 20,9 + 7,4 sm2 and 3,6 + 0,75 sm respectively by echocardiography.
Mean pulmonary arterial pressure and mean right atrial pressure were 53,1 + 12 / 7,2 + 6 mmHg according to the right heart catheterization.
The mean value of cardiac index was 2,1 + 0,6 l/min/m2. The mean distance in 6-minute walking test was 420 + 113 m.
According to the CPET the mean values of Vo2 peak and VE/Vco2 slope were 10,99 + 5,15 ml/kg/min and 46,2 + 19,78.
After the thorough analysis of clinical, functional and hemodynamic status of patients, we revealed, that majority of patients were belonged to the high-risk group (n = 26), and 10 patients were belonged to the intermediate risk group. However, after the CPET performing we got the results, showing that an additional 7 patients, who had been earlier in the intermediate risk group, had a high risk of mortality during 1 year. 9 patients were belonged to the low risk group, that was also confirmed by CPET data.
A significant negative correlation between the functional class (WHO) and VO2 peak in patients with PAH was found (r = −0,78; p < 0,0001).
Conclusions:
Risk stratification is crucial for the development of an appropriate treatment strategy. Patients who achieve the therapy goals, no matter which specific therapy or approach is used, seem to have a better prognosis than those who do not. The CPET is necessary for pathogenic therapy effectiveness assessment and for making decision of therapy escalation in patients with PAH.
